- ID:
- ivo://CDS.VizieR/J/ApJS/172/368
- Title:
- XMM-Newton survey in COSMOS field. IV.
- Short Name:
- J/ApJS/172/368
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed spectral analysis of pointlike X-ray sources in the XMM-Newton COSMOS field. Our sample of 135 sources only includes those that have more than 100 net counts in the 0.3-10keV energy band and have been identified through optical spectroscopy. The majority of the sources are well described by a simple power-law model with either no absorption (76%) or a significant intrinsic, absorbing column (20%). The remaining ~4% of the sources require a more complex modeling by incorporating additional components to the power law. For sources with more than 180 net counts (bright sample), we allowed both the photon spectral index Gamma and the equivalent hydrogen column NH to be free parameters. For fainter sources, we fix Gamma to the average value and allow NH to vary. The mean spectral index of the 82 sources in the bright sample is <Gamma>=2.06+/-0.08, with an intrinsic dispersion of ~0.24. Each of these sources has fractional errors on the value of Gamma below 20%. As expected, the distribution of intrinsic absorbing column densities is markedly different between AGNs with or without broad optical emission lines. We find within our sample four type 2 QSO candidates (L_X_>10^44^erg/s, NH>10^22^cm^-2^), with a spectral energy distribution well reproduced by a composite Seyfert 2 spectrum, that demonstrates the strength of the wide-field COSMOS XMM-Newton survey to detect these rare and underrepresented sources. In addition, we have identified a Compton-thick (NH>1.5x10^24^cm^-2^) AGN at z=0.1248. Its X-ray spectrum is well fitted by a pure reflection model and a significant Fe K{alpha} line at rest-frame energy of 6.4keV.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/466/41
- Title:
- XMM-Newton survey in the Marano Field. I.
- Short Name:
- J/A+A/466/41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on a medium deep XMM-Newton survey of the Marano Field and optical follow-up observations. The mosaicked XMM-Newton pointings in this optical quasar survey field cover 0.6 deg2 with a total of 120ks good observation time. We detected 328 X-ray sources in total. The turnover flux of our sample is f_X_~5x10^-15^erg/cm2/s in the 0.2-10keV band. With VLT FORS1 and FORS2 spectroscopy we classified 96 new X-ray counterparts. The central 0.28deg^2^, where detailed optical follow-up observations were performed, contain 170 X-ray sources (detection likelihood ML>10), out of which 48 had already been detected by ROSAT. In this region we recover 23 out of 29 optically selected quasars. With a total of 110 classifications in our core sample we reach a completeness of ~65%. About one-third of the XMM-Newton sources are classified as type II AGN with redshifts mostly below 1.0. Furthermore, we detect five high redshift type II AGN (2.2<=z<=2.8).
- ID:
- ivo://CDS.VizieR/J/A+A/469/1211
- Title:
- XMM-Newton survey of SA 57
- Short Name:
- J/A+A/469/1211
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The maximum number density of Active Galactic Nuclei (AGNs), as deduced from X-ray studies, occurs at z>=1, with lower luminosity objects peaking at smaller redshifts. Optical studies lead to a different evolutionary behaviour, with a number density peaking at z~2 independently of the intrinsic luminosity, but this result is limited to active nuclei brighter than the host galaxy. A selection based on optical variability can detect low luminosity AGNs (LLAGNs), where the host galaxy light prevents the identification by non-stellar colours. We want to collect X-ray data in a field where it exists an optically-selected sample of "variable galaxies", i.e. variable objects with diffuse appearance, to investigate the X-ray and optical properties of the population of AGNs, particularly of low luminosity ones, where the host galaxy is visible. We observed a field of ~0.2{deg}^2^ in the Selected Area 57, for 67ks with XMM-Newton. We detected X-ray sources, and we correlated the list with a photographic survey of SA 57, complete to B_J_~23 and with available spectroscopic data. We obtained a catalogue of 140 X-ray sources to limiting fluxes 5x10^-16^, 2x10^-15^erg/cm^2^/s in the 0.5-2keV and 2-10keV respectively, 98 of which are identified in the optical bands. The X-ray detection of part of the variability-selected candidates confirms their AGN nature. Diffuse variable objects populate the low luminosity side of the sample. Only 25/44 optically-selected QSOs are detected in X-rays. 15% of all QSOs in the field have X/O<0.1.
- ID:
- ivo://CDS.VizieR/J/A+A/457/501
- Title:
- XMM-Newton survey of the ELAIS-S1 field
- Short Name:
- J/A+A/457/501
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The formation and evolution of cosmic structures can be probed by studying the evolution of the luminosity function of the Active Galactic Nuclei (AGNs), galaxies and clusters of galaxies and of the clustering of the X-ray active Universe, compared to the IR-UV active Universe. To this purpose, we have surveyed with XMM-Newton the central ~0.6{deg}^2^ region of the ELAIS-S1 field down to flux limits of ~5.5x10^-16^erg/cm^2^/s (0.5-2keV, soft band, S), ~2x10^-15^erg/cm^2^/s (2-10keV, hard band, H), and ~4x10^-15^erg/cm^2^/s (5-10keV, ultra hard band, HH). We present here the analysis of the XMM-Newton observations, the number counts in different energy bands and the clustering properties of the X-ray sources.
- ID:
- ivo://CDS.VizieR/J/A+A/488/417
- Title:
- XMM-Newton survey of the ELAIS-S1 field. II.
- Short Name:
- J/A+A/488/417
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the optical identifications and a multi-band catalogue of a sample of 478 X-ray sources detected in the XMM-Newton and Chandra surveys of the central 0.6deg^2^ of the ELAIS-S1 field. The most likely optical/infrared counterpart of each X-ray source was identified using the chance coincidence probability in the R and IRAC 3.6 micron bands.This method was complemented by the precise positions obtained through Chandra observations. We were able to associate a counterpart to each X-ray source in the catalogue. Approximately 94% of them are detected in the R band, while the remaining are blank fields in the optical down to R~24.5, but have a near-infrared counterpart detected by IRAC within 6 arcsec from the XMM-Newton centroid. The multi-band catalogue, produced using the positions of the identified optical counterparts, contains photometry in ten photometric bands, from B to the MIPS 24 micron band. The spectroscopic follow-up allowed us to determine the redshift and classification for 237 sources (~50% of the sample) brighter than R=24. The spectroscopic redshifts were complemented by reliable photometric redshifts for 68 sources. We classified 47% of the sources with spectroscopic redshift as broad-line active galactic nuclei (BL AGNs) with z=0.1-3.5, while sources without broad-lines (NOT BL AGNs) are about 46% of the spectroscopic sample and are found up to z=2.6. The remaining fraction is represented by extended X-ray sources and stars. We spectroscopically identified 11 type 2 QSOs among the sources with X/O>8, with redshift between 0.9 and 2.6, high 2-10keV luminosity (logLx>=43.8erg/s) and hard X-ray colors suggesting large absorbing columns at the rest frame (logN_H_ up to 23.6cm^-2^). BL AGNs show on average blue optical-to-near-infrared colors, softer X-ray colors and X-ray-to-optical colors typical of optically selected AGNs. Conversely, narrow-line sources show redder optical colors, harder X-ray flux ratio and span a wider range of X-ray-to-optical colors. On average the Spectral Energy Distributions (SEDs) of high-luminosity BL AGNs resemble the power-law typical of unobscured AGNs. The SEDs of NOT BLAGNs are dominated by the galaxy emission in the optical/near-infrared, and show a rise in the mid-infrared which suggests the presence of an obscured active nucleus. We study the infrared-to-optical colors and near-infrared SEDs to infer the properties of the AGN host galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/557/A123
- Title:
- XMM-Newton Wide Angle Survey (XWAS)
- Short Name:
- J/A+A/557/A123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the XMM-Newton Wide Angle Survey (XWAS), a new catalogue of almost a thousand X-ray sources spectroscopically identified through optical observations. Sources lie in high-galactic latitude (|b|>20deg) XMM-Newton fields mainly in the southern hemisphere. A sample of X-ray sources detected in 68 XMM-Newton pointed observations was selected for optical multi-fibre spectroscopy. Optical counterparts and corresponding photometry of the X-ray sources were obtained from the SuperCOSMOS Sky Survey. Candidates for spectroscopy were initially selected with magnitudes down to R~21, with preference for X-ray sources having a flux F_0.5-4.5keV_>=10^-14^erg/s/cm2. Optical spectroscopic observations were made using the Two Degree Field of the Anglo Australian Telescope, and the resulting spectra were classified based on optical emission lines. We have identified through optical spectroscopy 940 X-ray sources over {Omega}~11.8deg^2^ of the sky. Source populations in our sample can be summarised as 65% broad line active galactic nuclei (BLAGN), 16% narrow emission line galaxies (NELGs), 6% absorption line galaxies (ALGs) and 13% stars. An active nucleus is also likely to be present in the large majority of the X-ray sources spectroscopically classified as NELGs or ALGs.
- ID:
- ivo://CDS.VizieR/J/A+A/497/635
- Title:
- XMM-Newton wide-field survey in COSMOS field
- Short Name:
- J/A+A/497/635
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The COSMOS survey is a multiwavelength survey aimed to study the evolution of galaxies, AGN and large scale structures. Within this survey XMM-COSMOS a powerful tool to detect AGN and galaxy clusters. The XMM-COSMOS is a deep X-ray survey over the full 2deg^2^ of the COSMOS area. It consists of 55 XMM-Newton pointings for a total exposure of ~1.5Ms with an average vignetting-corrected depth of 40ks across the field of view and a sky coverage of 2.13deg^2^. The analysis was performed using the XMM-SAS data analysis package in the 0.5-2keV, 2-10keV and 5-10keV energy bands. Source detection has been performed using a maximum likelihood technique especially designed for raster scan surveys. The completeness of the catalogue as well as logN-logS and source density maps have been calibrated using Monte Carlo simulations.
- ID:
- ivo://CDS.VizieR/J/A+A/444/79
- Title:
- XMM observations of Lockman Hole brightest AGNs
- Short Name:
- J/A+A/444/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents the results of a detailed X-ray spectral analysis of a sample of 123 X-ray sources detected with XMM-Newton in the Lockman Hole field. This is the deepest observation carried out with XMM-Newton with more that 600ks of good EPIC-pn data. We have spectra with good signal to noise (>500 source counts) for all objects down to 0.2-12keV fluxes of 5x10^-15^erg/cm^2^/s (flux limit of 6x10^-16^erg/cm^2^/s in the 0.5-2 and 2-10keV bands). At the time of the analysis, we had optical spectroscopic identifications for 60% of the sources, 46 being optical type-1 AGN and 28 optical type-2 AGN. Using a single power law model our sources' average spectral slope hardens at faint 0.5-2keV fluxes but not at faint 2-10keV fluxes.
- ID:
- ivo://CDS.VizieR/J/A+A/479/283
- Title:
- XMM observations of the Lockman Hole
- Short Name:
- J/A+A/479/283
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Lockman Hole represents the sky area of lowest Galactic line-of-sight columns density. It was observed by the XMM-Newton X-ray observatory in 18 pointings performed between April 2000 and December 2002. The total exposure time spent on the field was 1.16Ms (EPIC pn detector; EPIC MOS detector: 1.30 Ms). The effective exposure after removal of times of high particle background is 637ks (EPIC pn detector; EPIC MOS detector: 765ks). The catalogue lists positions, count rates, fluxes, hardness ratios, and partial optical classifications of 409 X-ray point sources detected in the central 0.196{deg}2 of the field down to a detection likelihood threshold of 10 (3.9sigma). The analysis was performed using the XMM-Newton SAS data analysis package version 6.0.
2160. XMMOMCDFS catalogue
- ID:
- ivo://CDS.VizieR/J/A+A/574/A49
- Title:
- XMMOMCDFS catalogue
- Short Name:
- J/A+A/574/A49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The XMM-Newton X-ray observatory has performed repeated observations of the CDFS in 33 epochs (2001-2010) through the XMM-CDFS Deep Survey. During the X-ray observations, XMM-OM targeted the central 17x17arcmin^2^ region of the X-ray field of view, providing simultaneous optical/UV coverage of the CDFS. The resulting set of data can be taken into account to build an XMM-OM catalogue of the CDFS, filling the UV spectral coverage between the optical surveys and GALEX observations. We present the UV catalogue of the XMM-CDFS Deep Survey. Its main purpose is to provide complementary UV average photometric measurements of known optical/UV sources in the CDFS, taking advantage of the unique characteristics of the survey. The data reduction is intended also to improve the standard source detection on individual observations, by cataloguing faint sources through the stacking of their exposure images. We reprocessed the XMM-OM data of the survey and we stacked the exposures from consecutive observations using the standard SAS tools to process the data obtained during single observations. Average measurements of detections with SAS good quality flags from individual observations and from stacked images have been joined to compile the catalogue. Sources have been validated through the cross-identification within the EIS and COMBO-17 surveys. Photometric data of 1129 CDFS sources are provided into the catalogue, and optical/UV/X-ray photometric and spectroscopic information from other surveys are also included. The stacking extends the detection limits by ~1 mag in the three UV bands, contributing 30% of the catalogued UV sources. The comparison with the available measurements in similar spectral bands confirms the validity of the XMM-OM calibration. The combined COMBO-17/X-ray classification of the "intermediate" sources (e.g. optically diluted and/or X-ray absorbed AGN) is also discussed.
